4 * Copyright Red Hat, Inc. 2012
7 * Paolo Bonzini <pbonzini@redhat.com>
9 * This work is licensed under the terms of the GNU LGPL, version 2 or later.
10 * See the COPYING.LIB file in the top-level directory.
14 #include "qemu/osdep.h"
15 #include "qemu/cutils.h"
16 #include "qemu/coroutine.h"
17 #include "qemu/range.h"
19 #include "block/blockjob_int.h"
20 #include "block/block_int.h"
21 #include "sysemu/block-backend.h"
22 #include "qapi/error.h"
23 #include "qapi/qmp/qerror.h"
24 #include "qemu/ratelimit.h"
25 #include "qemu/bitmap.h"
27 #define MAX_IN_FLIGHT 16
28 #define MAX_IO_BYTES (1 << 20) /* 1 Mb */
29 #define DEFAULT_MIRROR_BUF_SIZE (MAX_IN_FLIGHT * MAX_IO_BYTES)
31 /* The mirroring buffer is a list of granularity-sized chunks.
32 * Free chunks are organized in a list.
34 typedef struct MirrorBuffer
{
35 QSIMPLEQ_ENTRY(MirrorBuffer
) next
;
38 typedef struct MirrorOp MirrorOp
;
40 typedef struct MirrorBlockJob
{
43 BlockDriverState
*mirror_top_bs
;
44 BlockDriverState
*base
;
45 BlockDriverState
*base_overlay
;
47 /* The name of the graph node to replace */
49 /* The BDS to replace */
50 BlockDriverState
*to_replace
;
51 /* Used to block operations on the drive-mirror-replace target */
52 Error
*replace_blocker
;
54 BlockMirrorBackingMode backing_mode
;
55 /* Whether the target image requires explicit zero-initialization */
57 MirrorCopyMode copy_mode
;
58 BlockdevOnError on_source_error
, on_target_error
;
59 /* Set when the target is synced (dirty bitmap is clean, nothing
60 * in flight) and the job is running in active mode */
66 unsigned long *cow_bitmap
;
67 BdrvDirtyBitmap
*dirty_bitmap
;
68 BdrvDirtyBitmapIter
*dbi
;
70 QSIMPLEQ_HEAD(, MirrorBuffer
) buf_free
;
73 uint64_t last_pause_ns
;
74 unsigned long *in_flight_bitmap
;
76 int64_t bytes_in_flight
;
77 QTAILQ_HEAD(, MirrorOp
) ops_in_flight
;
80 int target_cluster_size
;
82 bool initial_zeroing_ongoing
;
83 int in_active_write_counter
;
88 typedef struct MirrorBDSOpaque
{
100 /* The pointee is set by mirror_co_read(), mirror_co_zero(), and
101 * mirror_co_discard() before yielding for the first time */
102 int64_t *bytes_handled
;
105 bool is_active_write
;
107 CoQueue waiting_requests
;
109 MirrorOp
*waiting_for_op
;
111 QTAILQ_ENTRY(MirrorOp
) next
;
114 typedef enum MirrorMethod
{
117 MIRROR_METHOD_DISCARD
,
120 static BlockErrorAction
mirror_error_action(MirrorBlockJob
*s
, bool read
,
123 s
->actively_synced
= false;
125 return block_job_error_action(&s
->common
, s
->on_source_error
,
128 return block_job_error_action(&s
->common
, s
->on_target_error
,
133 static void coroutine_fn
mirror_wait_on_conflicts(MirrorOp
*self
,
138 uint64_t self_start_chunk
= offset
/ s
->granularity
;
139 uint64_t self_end_chunk
= DIV_ROUND_UP(offset
+ bytes
, s
->granularity
);
140 uint64_t self_nb_chunks
= self_end_chunk
- self_start_chunk
;
142 while (find_next_bit(s
->in_flight_bitmap
, self_end_chunk
,
143 self_start_chunk
) < self_end_chunk
&&
148 QTAILQ_FOREACH(op
, &s
->ops_in_flight
, next
) {
149 uint64_t op_start_chunk
= op
->offset
/ s
->granularity
;
150 uint64_t op_nb_chunks
= DIV_ROUND_UP(op
->offset
+ op
->bytes
,
158 if (ranges_overlap(self_start_chunk
, self_nb_chunks
,
159 op_start_chunk
, op_nb_chunks
))
163 * If the operation is already (indirectly) waiting for us,
164 * or will wait for us as soon as it wakes up, then just go
165 * on (instead of producing a deadlock in the former case).
167 if (op
->waiting_for_op
) {
171 self
->waiting_for_op
= op
;
174 qemu_co_queue_wait(&op
->waiting_requests
, NULL
);
177 self
->waiting_for_op
= NULL
;
186 static void coroutine_fn
mirror_iteration_done(MirrorOp
*op
, int ret
)
188 MirrorBlockJob
*s
= op
->s
;
193 trace_mirror_iteration_done(s
, op
->offset
, op
->bytes
, ret
);
196 s
->bytes_in_flight
-= op
->bytes
;
198 for (i
= 0; i
< op
->qiov
.niov
; i
++) {
199 MirrorBuffer
*buf
= (MirrorBuffer
*) iov
[i
].iov_base
;
200 QSIMPLEQ_INSERT_TAIL(&s
->buf_free
, buf
, next
);
204 chunk_num
= op
->offset
/ s
->granularity
;
205 nb_chunks
= DIV_ROUND_UP(op
->bytes
, s
->granularity
);
207 bitmap_clear(s
->in_flight_bitmap
, chunk_num
, nb_chunks
);
208 QTAILQ_REMOVE(&s
->ops_in_flight
, op
, next
);
211 bitmap_set(s
->cow_bitmap
, chunk_num
, nb_chunks
);
213 if (!s
->initial_zeroing_ongoing
) {
214 job_progress_update(&s
->common
.job
, op
->bytes
);
217 qemu_iovec_destroy(&op
->qiov
);
219 qemu_co_queue_restart_all(&op
->waiting_requests
);
223 static void coroutine_fn
mirror_write_complete(MirrorOp
*op
, int ret
)
225 MirrorBlockJob
*s
= op
->s
;
228 BlockErrorAction action
;
230 bdrv_set_dirty_bitmap(s
->dirty_bitmap
, op
->offset
, op
->bytes
);
231 action
= mirror_error_action(s
, false, -ret
);
232 if (action
== BLOCK_ERROR_ACTION_REPORT
&& s
->ret
>= 0) {
237 mirror_iteration_done(op
, ret
);
240 static void coroutine_fn
mirror_read_complete(MirrorOp
*op
, int ret
)
242 MirrorBlockJob
*s
= op
->s
;
245 BlockErrorAction action
;
247 bdrv_set_dirty_bitmap(s
->dirty_bitmap
, op
->offset
, op
->bytes
);
248 action
= mirror_error_action(s
, true, -ret
);
249 if (action
== BLOCK_ERROR_ACTION_REPORT
&& s
->ret
>= 0) {
253 mirror_iteration_done(op
, ret
);
257 ret
= blk_co_pwritev(s
->target
, op
->offset
, op
->qiov
.size
, &op
->qiov
, 0);
258 mirror_write_complete(op
, ret
);
261 /* Clip bytes relative to offset to not exceed end-of-file */
262 static inline int64_t mirror_clip_bytes(MirrorBlockJob
*s
,
266 return MIN(bytes
, s
->bdev_length
- offset
);
269 /* Round offset and/or bytes to target cluster if COW is needed, and
270 * return the offset of the adjusted tail against original. */
271 static int mirror_cow_align(MirrorBlockJob
*s
, int64_t *offset
,
276 int64_t align_offset
= *offset
;
277 int64_t align_bytes
= *bytes
;
278 int max_bytes
= s
->granularity
* s
->max_iov
;
280 need_cow
= !test_bit(*offset
/ s
->granularity
, s
->cow_bitmap
);
281 need_cow
|= !test_bit((*offset
+ *bytes
- 1) / s
->granularity
,
284 bdrv_round_to_clusters(blk_bs(s
->target
), *offset
, *bytes
,
285 &align_offset
, &align_bytes
);
288 if (align_bytes
> max_bytes
) {
289 align_bytes
= max_bytes
;
291 align_bytes
= QEMU_ALIGN_DOWN(align_bytes
, s
->target_cluster_size
);
294 /* Clipping may result in align_bytes unaligned to chunk boundary, but
295 * that doesn't matter because it's already the end of source image. */
296 align_bytes
= mirror_clip_bytes(s
, align_offset
, align_bytes
);
298 ret
= align_offset
+ align_bytes
- (*offset
+ *bytes
);
299 *offset
= align_offset
;
300 *bytes
= align_bytes
;
305 static inline void coroutine_fn
306 mirror_wait_for_any_operation(MirrorBlockJob
*s
, bool active
)
310 QTAILQ_FOREACH(op
, &s
->ops_in_flight
, next
) {
311 /* Do not wait on pseudo ops, because it may in turn wait on
312 * some other operation to start, which may in fact be the
313 * caller of this function. Since there is only one pseudo op
314 * at any given time, we will always find some real operation
316 if (!op
->is_pseudo_op
&& op
->is_in_flight
&&
317 op
->is_active_write
== active
)
319 qemu_co_queue_wait(&op
->waiting_requests
, NULL
);
326 static inline void coroutine_fn
327 mirror_wait_for_free_in_flight_slot(MirrorBlockJob
*s
)
329 /* Only non-active operations use up in-flight slots */
330 mirror_wait_for_any_operation(s
, false);
333 /* Perform a mirror copy operation.
335 * *op->bytes_handled is set to the number of bytes copied after and
336 * including offset, excluding any bytes copied prior to offset due
337 * to alignment. This will be op->bytes if no alignment is necessary,
338 * or (new_end - op->offset) if the tail is rounded up or down due to
339 * alignment or buffer limit.
341 static void coroutine_fn
mirror_co_read(void *opaque
)
343 MirrorOp
*op
= opaque
;
344 MirrorBlockJob
*s
= op
->s
;
349 max_bytes
= s
->granularity
* s
->max_iov
;
351 /* We can only handle as much as buf_size at a time. */
352 op
->bytes
= MIN(s
->buf_size
, MIN(max_bytes
, op
->bytes
));
354 assert(op
->bytes
< BDRV_REQUEST_MAX_BYTES
);
355 *op
->bytes_handled
= op
->bytes
;
358 *op
->bytes_handled
+= mirror_cow_align(s
, &op
->offset
, &op
->bytes
);
360 /* Cannot exceed BDRV_REQUEST_MAX_BYTES + INT_MAX */
361 assert(*op
->bytes_handled
<= UINT_MAX
);
362 assert(op
->bytes
<= s
->buf_size
);
363 /* The offset is granularity-aligned because:
364 * 1) Caller passes in aligned values;
365 * 2) mirror_cow_align is used only when target cluster is larger. */
366 assert(QEMU_IS_ALIGNED(op
->offset
, s
->granularity
));
367 /* The range is sector-aligned, since bdrv_getlength() rounds up. */
368 assert(QEMU_IS_ALIGNED(op
->bytes
, BDRV_SECTOR_SIZE
));
369 nb_chunks
= DIV_ROUND_UP(op
->bytes
, s
->granularity
);
371 while (s
->buf_free_count
< nb_chunks
) {
372 trace_mirror_yield_in_flight(s
, op
->offset
, s
->in_flight
);
373 mirror_wait_for_free_in_flight_slot(s
);
376 /* Now make a QEMUIOVector taking enough granularity-sized chunks
379 qemu_iovec_init(&op
->qiov
, nb_chunks
);
380 while (nb_chunks
-- > 0) {
381 MirrorBuffer
*buf
= QSIMPLEQ_FIRST(&s
->buf_free
);
382 size_t remaining
= op
->bytes
- op
->qiov
.size
;
384 QSIMPLEQ_REMOVE_HEAD(&s
->buf_free
, next
);
386 qemu_iovec_add(&op
->qiov
, buf
, MIN(s
->granularity
, remaining
));
389 /* Copy the dirty cluster. */
391 s
->bytes_in_flight
+= op
->bytes
;
392 op
->is_in_flight
= true;
393 trace_mirror_one_iteration(s
, op
->offset
, op
->bytes
);
395 ret
= bdrv_co_preadv(s
->mirror_top_bs
->backing
, op
->offset
, op
->bytes
,
397 mirror_read_complete(op
, ret
);
400 static void coroutine_fn
mirror_co_zero(void *opaque
)
402 MirrorOp
*op
= opaque
;
406 op
->s
->bytes_in_flight
+= op
->bytes
;
407 *op
->bytes_handled
= op
->bytes
;
408 op
->is_in_flight
= true;
410 ret
= blk_co_pwrite_zeroes(op
->s
->target
, op
->offset
, op
->bytes
,
411 op
->s
->unmap
? BDRV_REQ_MAY_UNMAP
: 0);
412 mirror_write_complete(op
, ret
);
415 static void coroutine_fn
mirror_co_discard(void *opaque
)
417 MirrorOp
*op
= opaque
;
421 op
->s
->bytes_in_flight
+= op
->bytes
;
422 *op
->bytes_handled
= op
->bytes
;
423 op
->is_in_flight
= true;
425 ret
= blk_co_pdiscard(op
->s
->target
, op
->offset
, op
->bytes
);
426 mirror_write_complete(op
, ret
);
429 static unsigned mirror_perform(MirrorBlockJob
*s
, int64_t offset
,
430 unsigned bytes
, MirrorMethod mirror_method
)
434 int64_t bytes_handled
= -1;
436 op
= g_new(MirrorOp
, 1);
441 .bytes_handled
= &bytes_handled
,
443 qemu_co_queue_init(&op
->waiting_requests
);
445 switch (mirror_method
) {
446 case MIRROR_METHOD_COPY
:
447 co
= qemu_coroutine_create(mirror_co_read
, op
);
449 case MIRROR_METHOD_ZERO
:
450 co
= qemu_coroutine_create(mirror_co_zero
, op
);
452 case MIRROR_METHOD_DISCARD
:
453 co
= qemu_coroutine_create(mirror_co_discard
, op
);
460 QTAILQ_INSERT_TAIL(&s
->ops_in_flight
, op
, next
);
461 qemu_coroutine_enter(co
);
462 /* At this point, ownership of op has been moved to the coroutine
463 * and the object may already be freed */
465 /* Assert that this value has been set */
466 assert(bytes_handled
>= 0);
468 /* Same assertion as in mirror_co_read() (and for mirror_co_read()
469 * and mirror_co_discard(), bytes_handled == op->bytes, which
470 * is the @bytes parameter given to this function) */
471 assert(bytes_handled
<= UINT_MAX
);
472 return bytes_handled
;
475 static uint64_t coroutine_fn
mirror_iteration(MirrorBlockJob
*s
)
477 BlockDriverState
*source
= s
->mirror_top_bs
->backing
->bs
;
480 uint64_t delay_ns
= 0, ret
= 0;
481 /* At least the first dirty chunk is mirrored in one iteration. */
483 bool write_zeroes_ok
= bdrv_can_write_zeroes_with_unmap(blk_bs(s
->target
));
484 int max_io_bytes
= MAX(s
->buf_size
/ MAX_IN_FLIGHT
, MAX_IO_BYTES
);
486 bdrv_dirty_bitmap_lock(s
->dirty_bitmap
);
487 offset
= bdrv_dirty_iter_next(s
->dbi
);
489 bdrv_set_dirty_iter(s
->dbi
, 0);
490 offset
= bdrv_dirty_iter_next(s
->dbi
);
491 trace_mirror_restart_iter(s
, bdrv_get_dirty_count(s
->dirty_bitmap
));
494 bdrv_dirty_bitmap_unlock(s
->dirty_bitmap
);
496 mirror_wait_on_conflicts(NULL
, s
, offset
, 1);
498 job_pause_point(&s
->common
.job
);
500 /* Find the number of consective dirty chunks following the first dirty
501 * one, and wait for in flight requests in them. */
502 bdrv_dirty_bitmap_lock(s
->dirty_bitmap
);
503 while (nb_chunks
* s
->granularity
< s
->buf_size
) {
505 int64_t next_offset
= offset
+ nb_chunks
* s
->granularity
;
506 int64_t next_chunk
= next_offset
/ s
->granularity
;
507 if (next_offset
>= s
->bdev_length
||
508 !bdrv_dirty_bitmap_get_locked(s
->dirty_bitmap
, next_offset
)) {
511 if (test_bit(next_chunk
, s
->in_flight_bitmap
)) {
515 next_dirty
= bdrv_dirty_iter_next(s
->dbi
);
516 if (next_dirty
> next_offset
|| next_dirty
< 0) {
517 /* The bitmap iterator's cache is stale, refresh it */
518 bdrv_set_dirty_iter(s
->dbi
, next_offset
);
519 next_dirty
= bdrv_dirty_iter_next(s
->dbi
);
521 assert(next_dirty
== next_offset
);
525 /* Clear dirty bits before querying the block status, because
526 * calling bdrv_block_status_above could yield - if some blocks are
527 * marked dirty in this window, we need to know.
529 bdrv_reset_dirty_bitmap_locked(s
->dirty_bitmap
, offset
,
530 nb_chunks
* s
->granularity
);
531 bdrv_dirty_bitmap_unlock(s
->dirty_bitmap
);
533 /* Before claiming an area in the in-flight bitmap, we have to
534 * create a MirrorOp for it so that conflicting requests can wait
535 * for it. mirror_perform() will create the real MirrorOps later,
536 * for now we just create a pseudo operation that will wake up all
537 * conflicting requests once all real operations have been
539 pseudo_op
= g_new(MirrorOp
, 1);
540 *pseudo_op
= (MirrorOp
){
542 .bytes
= nb_chunks
* s
->granularity
,
543 .is_pseudo_op
= true,
545 qemu_co_queue_init(&pseudo_op
->waiting_requests
);
546 QTAILQ_INSERT_TAIL(&s
->ops_in_flight
, pseudo_op
, next
);
548 bitmap_set(s
->in_flight_bitmap
, offset
/ s
->granularity
, nb_chunks
);
549 while (nb_chunks
> 0 && offset
< s
->bdev_length
) {
552 int64_t io_bytes_acct
;
553 MirrorMethod mirror_method
= MIRROR_METHOD_COPY
;
555 assert(!(offset
% s
->granularity
));
556 ret
= bdrv_block_status_above(source
, NULL
, offset
,
557 nb_chunks
* s
->granularity
,
558 &io_bytes
, NULL
, NULL
);
560 io_bytes
= MIN(nb_chunks
* s
->granularity
, max_io_bytes
);
561 } else if (ret
& BDRV_BLOCK_DATA
) {
562 io_bytes
= MIN(io_bytes
, max_io_bytes
);
565 io_bytes
-= io_bytes
% s
->granularity
;
566 if (io_bytes
< s
->granularity
) {
567 io_bytes
= s
->granularity
;
568 } else if (ret
>= 0 && !(ret
& BDRV_BLOCK_DATA
)) {
569 int64_t target_offset
;
570 int64_t target_bytes
;
571 bdrv_round_to_clusters(blk_bs(s
->target
), offset
, io_bytes
,
572 &target_offset
, &target_bytes
);
573 if (target_offset
== offset
&&
574 target_bytes
== io_bytes
) {
575 mirror_method
= ret
& BDRV_BLOCK_ZERO
?
577 MIRROR_METHOD_DISCARD
;
581 while (s
->in_flight
>= MAX_IN_FLIGHT
) {
582 trace_mirror_yield_in_flight(s
, offset
, s
->in_flight
);
583 mirror_wait_for_free_in_flight_slot(s
);
591 io_bytes
= mirror_clip_bytes(s
, offset
, io_bytes
);
592 io_bytes
= mirror_perform(s
, offset
, io_bytes
, mirror_method
);
593 if (mirror_method
!= MIRROR_METHOD_COPY
&& write_zeroes_ok
) {
596 io_bytes_acct
= io_bytes
;
600 nb_chunks
-= DIV_ROUND_UP(io_bytes
, s
->granularity
);
601 delay_ns
= block_job_ratelimit_get_delay(&s
->common
, io_bytes_acct
);
606 QTAILQ_REMOVE(&s
->ops_in_flight
, pseudo_op
, next
);
607 qemu_co_queue_restart_all(&pseudo_op
->waiting_requests
);
613 static void mirror_free_init(MirrorBlockJob
*s
)
615 int granularity
= s
->granularity
;
616 size_t buf_size
= s
->buf_size
;
617 uint8_t *buf
= s
->buf
;
619 assert(s
->buf_free_count
== 0);
620 QSIMPLEQ_INIT(&s
->buf_free
);
621 while (buf_size
!= 0) {
622 MirrorBuffer
*cur
= (MirrorBuffer
*)buf
;
623 QSIMPLEQ_INSERT_TAIL(&s
->buf_free
, cur
, next
);
625 buf_size
-= granularity
;
630 /* This is also used for the .pause callback. There is no matching
631 * mirror_resume() because mirror_run() will begin iterating again
632 * when the job is resumed.
634 static void coroutine_fn
mirror_wait_for_all_io(MirrorBlockJob
*s
)
636 while (s
->in_flight
> 0) {
637 mirror_wait_for_free_in_flight_slot(s
);
642 * mirror_exit_common: handle both abort() and prepare() cases.
643 * for .prepare, returns 0 on success and -errno on failure.
644 * for .abort cases, denoted by abort = true, MUST return 0.
646 static int mirror_exit_common(Job
*job
)
648 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
.job
);
649 BlockJob
*bjob
= &s
->common
;
650 MirrorBDSOpaque
*bs_opaque
;
651 AioContext
*replace_aio_context
= NULL
;
652 BlockDriverState
*src
;
653 BlockDriverState
*target_bs
;
654 BlockDriverState
*mirror_top_bs
;
655 Error
*local_err
= NULL
;
656 bool abort
= job
->ret
< 0;
664 mirror_top_bs
= s
->mirror_top_bs
;
665 bs_opaque
= mirror_top_bs
->opaque
;
666 src
= mirror_top_bs
->backing
->bs
;
667 target_bs
= blk_bs(s
->target
);
669 if (bdrv_chain_contains(src
, target_bs
)) {
670 bdrv_unfreeze_backing_chain(mirror_top_bs
, target_bs
);
673 bdrv_release_dirty_bitmap(s
->dirty_bitmap
);
675 /* Make sure that the source BDS doesn't go away during bdrv_replace_node,
676 * before we can call bdrv_drained_end */
678 bdrv_ref(mirror_top_bs
);
682 * Remove target parent that still uses BLK_PERM_WRITE/RESIZE before
683 * inserting target_bs at s->to_replace, where we might not be able to get
686 blk_unref(s
->target
);
689 /* We don't access the source any more. Dropping any WRITE/RESIZE is
690 * required before it could become a backing file of target_bs. Not having
691 * these permissions any more means that we can't allow any new requests on
692 * mirror_top_bs from now on, so keep it drained. */
693 bdrv_drained_begin(mirror_top_bs
);
694 bs_opaque
->stop
= true;
695 bdrv_child_refresh_perms(mirror_top_bs
, mirror_top_bs
->backing
,
697 if (!abort
&& s
->backing_mode
== MIRROR_SOURCE_BACKING_CHAIN
) {
698 BlockDriverState
*backing
= s
->is_none_mode
? src
: s
->base
;
699 BlockDriverState
*unfiltered_target
= bdrv_skip_filters(target_bs
);
701 if (bdrv_cow_bs(unfiltered_target
) != backing
) {
702 bdrv_set_backing_hd(unfiltered_target
, backing
, &local_err
);
704 error_report_err(local_err
);
709 } else if (!abort
&& s
->backing_mode
== MIRROR_OPEN_BACKING_CHAIN
) {
710 assert(!bdrv_backing_chain_next(target_bs
));
711 ret
= bdrv_open_backing_file(bdrv_skip_filters(target_bs
), NULL
,
712 "backing", &local_err
);
714 error_report_err(local_err
);
720 replace_aio_context
= bdrv_get_aio_context(s
->to_replace
);
721 aio_context_acquire(replace_aio_context
);
724 if (s
->should_complete
&& !abort
) {
725 BlockDriverState
*to_replace
= s
->to_replace
?: src
;
726 bool ro
= bdrv_is_read_only(to_replace
);
728 if (ro
!= bdrv_is_read_only(target_bs
)) {
729 bdrv_reopen_set_read_only(target_bs
, ro
, NULL
);
732 /* The mirror job has no requests in flight any more, but we need to
733 * drain potential other users of the BDS before changing the graph. */
735 bdrv_drained_begin(target_bs
);
737 * Cannot use check_to_replace_node() here, because that would
738 * check for an op blocker on @to_replace, and we have our own
741 if (bdrv_recurse_can_replace(src
, to_replace
)) {
742 bdrv_replace_node(to_replace
, target_bs
, &local_err
);
744 error_setg(&local_err
, "Can no longer replace '%s' by '%s', "
745 "because it can no longer be guaranteed that doing so "
746 "would not lead to an abrupt change of visible data",
747 to_replace
->node_name
, target_bs
->node_name
);
749 bdrv_drained_end(target_bs
);
751 error_report_err(local_err
);
756 bdrv_op_unblock_all(s
->to_replace
, s
->replace_blocker
);
757 error_free(s
->replace_blocker
);
758 bdrv_unref(s
->to_replace
);
760 if (replace_aio_context
) {
761 aio_context_release(replace_aio_context
);
764 bdrv_unref(target_bs
);
767 * Remove the mirror filter driver from the graph. Before this, get rid of
768 * the blockers on the intermediate nodes so that the resulting state is
771 block_job_remove_all_bdrv(bjob
);
772 bdrv_replace_node(mirror_top_bs
, mirror_top_bs
->backing
->bs
, &error_abort
);
774 bs_opaque
->job
= NULL
;
776 bdrv_drained_end(src
);
777 bdrv_drained_end(mirror_top_bs
);
779 bdrv_unref(mirror_top_bs
);
785 static int mirror_prepare(Job
*job
)
787 return mirror_exit_common(job
);
790 static void mirror_abort(Job
*job
)
792 int ret
= mirror_exit_common(job
);
796 static void coroutine_fn
mirror_throttle(MirrorBlockJob
*s
)
798 int64_t now
= qemu_clock_get_ns(QEMU_CLOCK_REALTIME
);
800 if (now
- s
->last_pause_ns
> BLOCK_JOB_SLICE_TIME
) {
801 s
->last_pause_ns
= now
;
802 job_sleep_ns(&s
->common
.job
, 0);
804 job_pause_point(&s
->common
.job
);
808 static int coroutine_fn
mirror_dirty_init(MirrorBlockJob
*s
)
811 BlockDriverState
*bs
= s
->mirror_top_bs
->backing
->bs
;
812 BlockDriverState
*target_bs
= blk_bs(s
->target
);
816 if (s
->zero_target
) {
817 if (!bdrv_can_write_zeroes_with_unmap(target_bs
)) {
818 bdrv_set_dirty_bitmap(s
->dirty_bitmap
, 0, s
->bdev_length
);
822 s
->initial_zeroing_ongoing
= true;
823 for (offset
= 0; offset
< s
->bdev_length
; ) {
824 int bytes
= MIN(s
->bdev_length
- offset
,
825 QEMU_ALIGN_DOWN(INT_MAX
, s
->granularity
));
829 if (job_is_cancelled(&s
->common
.job
)) {
830 s
->initial_zeroing_ongoing
= false;
834 if (s
->in_flight
>= MAX_IN_FLIGHT
) {
835 trace_mirror_yield(s
, UINT64_MAX
, s
->buf_free_count
,
837 mirror_wait_for_free_in_flight_slot(s
);
841 mirror_perform(s
, offset
, bytes
, MIRROR_METHOD_ZERO
);
845 mirror_wait_for_all_io(s
);
846 s
->initial_zeroing_ongoing
= false;
849 /* First part, loop on the sectors and initialize the dirty bitmap. */
850 for (offset
= 0; offset
< s
->bdev_length
; ) {
851 /* Just to make sure we are not exceeding int limit. */
852 int bytes
= MIN(s
->bdev_length
- offset
,
853 QEMU_ALIGN_DOWN(INT_MAX
, s
->granularity
));
857 if (job_is_cancelled(&s
->common
.job
)) {
861 ret
= bdrv_is_allocated_above(bs
, s
->base_overlay
, true, offset
, bytes
,
869 bdrv_set_dirty_bitmap(s
->dirty_bitmap
, offset
, count
);
876 /* Called when going out of the streaming phase to flush the bulk of the
877 * data to the medium, or just before completing.
879 static int mirror_flush(MirrorBlockJob
*s
)
881 int ret
= blk_flush(s
->target
);
883 if (mirror_error_action(s
, false, -ret
) == BLOCK_ERROR_ACTION_REPORT
) {
890 static int coroutine_fn
mirror_run(Job
*job
, Error
**errp
)
892 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
.job
);
893 BlockDriverState
*bs
= s
->mirror_top_bs
->backing
->bs
;
894 BlockDriverState
*target_bs
= blk_bs(s
->target
);
895 bool need_drain
= true;
897 int64_t target_length
;
899 char backing_filename
[2]; /* we only need 2 characters because we are only
900 checking for a NULL string */
903 if (job_is_cancelled(&s
->common
.job
)) {
907 s
->bdev_length
= bdrv_getlength(bs
);
908 if (s
->bdev_length
< 0) {
909 ret
= s
->bdev_length
;
913 target_length
= blk_getlength(s
->target
);
914 if (target_length
< 0) {
919 /* Active commit must resize the base image if its size differs from the
921 if (s
->base
== blk_bs(s
->target
)) {
922 if (s
->bdev_length
> target_length
) {
923 ret
= blk_truncate(s
->target
, s
->bdev_length
, false,
924 PREALLOC_MODE_OFF
, 0, NULL
);
929 } else if (s
->bdev_length
!= target_length
) {
930 error_setg(errp
, "Source and target image have different sizes");
935 if (s
->bdev_length
== 0) {
936 /* Transition to the READY state and wait for complete. */
937 job_transition_to_ready(&s
->common
.job
);
938 s
->actively_synced
= true;
939 while (!job_cancel_requested(&s
->common
.job
) && !s
->should_complete
) {
940 job_yield(&s
->common
.job
);
945 length
= DIV_ROUND_UP(s
->bdev_length
, s
->granularity
);
946 s
->in_flight_bitmap
= bitmap_new(length
);
948 /* If we have no backing file yet in the destination, we cannot let
949 * the destination do COW. Instead, we copy sectors around the
950 * dirty data if needed. We need a bitmap to do that.
952 bdrv_get_backing_filename(target_bs
, backing_filename
,
953 sizeof(backing_filename
));
954 if (!bdrv_get_info(target_bs
, &bdi
) && bdi
.cluster_size
) {
955 s
->target_cluster_size
= bdi
.cluster_size
;
957 s
->target_cluster_size
= BDRV_SECTOR_SIZE
;
959 if (backing_filename
[0] && !bdrv_backing_chain_next(target_bs
) &&
960 s
->granularity
< s
->target_cluster_size
) {
961 s
->buf_size
= MAX(s
->buf_size
, s
->target_cluster_size
);
962 s
->cow_bitmap
= bitmap_new(length
);
964 s
->max_iov
= MIN(bs
->bl
.max_iov
, target_bs
->bl
.max_iov
);
966 s
->buf
= qemu_try_blockalign(bs
, s
->buf_size
);
967 if (s
->buf
== NULL
) {
974 s
->last_pause_ns
= qemu_clock_get_ns(QEMU_CLOCK_REALTIME
);
975 if (!s
->is_none_mode
) {
976 ret
= mirror_dirty_init(s
);
977 if (ret
< 0 || job_is_cancelled(&s
->common
.job
)) {
983 s
->dbi
= bdrv_dirty_iter_new(s
->dirty_bitmap
);
985 uint64_t delay_ns
= 0;
987 bool should_complete
;
989 /* Do not start passive operations while there are active
990 * writes in progress */
991 while (s
->in_active_write_counter
) {
992 mirror_wait_for_any_operation(s
, true);
1000 job_pause_point(&s
->common
.job
);
1002 if (job_is_cancelled(&s
->common
.job
)) {
1004 goto immediate_exit
;
1007 cnt
= bdrv_get_dirty_count(s
->dirty_bitmap
);
1008 /* cnt is the number of dirty bytes remaining and s->bytes_in_flight is
1009 * the number of bytes currently being processed; together those are
1010 * the current remaining operation length */
1011 job_progress_set_remaining(&s
->common
.job
, s
->bytes_in_flight
+ cnt
);
1013 /* Note that even when no rate limit is applied we need to yield
1014 * periodically with no pending I/O so that bdrv_drain_all() returns.
1015 * We do so every BLKOCK_JOB_SLICE_TIME nanoseconds, or when there is
1016 * an error, or when the source is clean, whichever comes first. */
1017 delta
= qemu_clock_get_ns(QEMU_CLOCK_REALTIME
) - s
->last_pause_ns
;
1018 if (delta
< BLOCK_JOB_SLICE_TIME
&&
1019 s
->common
.iostatus
== BLOCK_DEVICE_IO_STATUS_OK
) {
1020 if (s
->in_flight
>= MAX_IN_FLIGHT
|| s
->buf_free_count
== 0 ||
1021 (cnt
== 0 && s
->in_flight
> 0)) {
1022 trace_mirror_yield(s
, cnt
, s
->buf_free_count
, s
->in_flight
);
1023 mirror_wait_for_free_in_flight_slot(s
);
1025 } else if (cnt
!= 0) {
1026 delay_ns
= mirror_iteration(s
);
1030 should_complete
= false;
1031 if (s
->in_flight
== 0 && cnt
== 0) {
1032 trace_mirror_before_flush(s
);
1033 if (!job_is_ready(&s
->common
.job
)) {
1034 if (mirror_flush(s
) < 0) {
1035 /* Go check s->ret. */
1038 /* We're out of the streaming phase. From now on, if the job
1039 * is cancelled we will actually complete all pending I/O and
1040 * report completion. This way, block-job-cancel will leave
1041 * the target in a consistent state.
1043 job_transition_to_ready(&s
->common
.job
);
1044 if (s
->copy_mode
!= MIRROR_COPY_MODE_BACKGROUND
) {
1045 s
->actively_synced
= true;
1049 should_complete
= s
->should_complete
||
1050 job_cancel_requested(&s
->common
.job
);
1051 cnt
= bdrv_get_dirty_count(s
->dirty_bitmap
);
1054 if (cnt
== 0 && should_complete
) {
1055 /* The dirty bitmap is not updated while operations are pending.
1056 * If we're about to exit, wait for pending operations before
1057 * calling bdrv_get_dirty_count(bs), or we may exit while the
1058 * source has dirty data to copy!
1060 * Note that I/O can be submitted by the guest while
1061 * mirror_populate runs, so pause it now. Before deciding
1062 * whether to switch to target check one last time if I/O has
1063 * come in the meanwhile, and if not flush the data to disk.
1065 trace_mirror_before_drain(s
, cnt
);
1068 bdrv_drained_begin(bs
);
1069 cnt
= bdrv_get_dirty_count(s
->dirty_bitmap
);
1070 if (cnt
> 0 || mirror_flush(s
) < 0) {
1071 bdrv_drained_end(bs
);
1072 s
->in_drain
= false;
1076 /* The two disks are in sync. Exit and report successful
1079 assert(QLIST_EMPTY(&bs
->tracked_requests
));
1084 if (job_is_ready(&s
->common
.job
) && !should_complete
) {
1085 delay_ns
= (s
->in_flight
== 0 &&
1086 cnt
== 0 ? BLOCK_JOB_SLICE_TIME
: 0);
1088 trace_mirror_before_sleep(s
, cnt
, job_is_ready(&s
->common
.job
),
1090 job_sleep_ns(&s
->common
.job
, delay_ns
);
1091 s
->last_pause_ns
= qemu_clock_get_ns(QEMU_CLOCK_REALTIME
);
1095 if (s
->in_flight
> 0) {
1096 /* We get here only if something went wrong. Either the job failed,
1097 * or it was cancelled prematurely so that we do not guarantee that
1098 * the target is a copy of the source.
1100 assert(ret
< 0 || job_is_cancelled(&s
->common
.job
));
1102 mirror_wait_for_all_io(s
);
1105 assert(s
->in_flight
== 0);
1107 g_free(s
->cow_bitmap
);
1108 g_free(s
->in_flight_bitmap
);
1109 bdrv_dirty_iter_free(s
->dbi
);
1113 bdrv_drained_begin(bs
);
1119 static void mirror_complete(Job
*job
, Error
**errp
)
1121 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
.job
);
1123 if (!job_is_ready(job
)) {
1124 error_setg(errp
, "The active block job '%s' cannot be completed",
1129 /* block all operations on to_replace bs */
1131 AioContext
*replace_aio_context
;
1133 s
->to_replace
= bdrv_find_node(s
->replaces
);
1134 if (!s
->to_replace
) {
1135 error_setg(errp
, "Node name '%s' not found", s
->replaces
);
1139 replace_aio_context
= bdrv_get_aio_context(s
->to_replace
);
1140 aio_context_acquire(replace_aio_context
);
1142 /* TODO Translate this into child freeze system. */
1143 error_setg(&s
->replace_blocker
,
1144 "block device is in use by block-job-complete");
1145 bdrv_op_block_all(s
->to_replace
, s
->replace_blocker
);
1146 bdrv_ref(s
->to_replace
);
1148 aio_context_release(replace_aio_context
);
1151 s
->should_complete
= true;
1153 /* If the job is paused, it will be re-entered when it is resumed */
1159 static void coroutine_fn
mirror_pause(Job
*job
)
1161 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
.job
);
1163 mirror_wait_for_all_io(s
);
1166 static bool mirror_drained_poll(BlockJob
*job
)
1168 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
);
1170 /* If the job isn't paused nor cancelled, we can't be sure that it won't
1171 * issue more requests. We make an exception if we've reached this point
1172 * from one of our own drain sections, to avoid a deadlock waiting for
1175 if (!s
->common
.job
.paused
&& !job_is_cancelled(&job
->job
) && !s
->in_drain
) {
1179 return !!s
->in_flight
;
1182 static bool mirror_cancel(Job
*job
, bool force
)
1184 MirrorBlockJob
*s
= container_of(job
, MirrorBlockJob
, common
.job
);
1185 BlockDriverState
*target
= blk_bs(s
->target
);
1188 * Before the job is READY, we treat any cancellation like a
1189 * force-cancellation.
1191 force
= force
|| !job_is_ready(job
);
1194 bdrv_cancel_in_flight(target
);
1199 static bool commit_active_cancel(Job
*job
, bool force
)
1201 /* Same as above in mirror_cancel() */
1202 return force
|| !job_is_ready(job
);
1205 static const BlockJobDriver mirror_job_driver
= {
1207 .instance_size
= sizeof(MirrorBlockJob
),
1208 .job_type
= JOB_TYPE_MIRROR
,
1209 .free
= block_job_free
,
1210 .user_resume
= block_job_user_resume
,
1212 .prepare
= mirror_prepare
,
1213 .abort
= mirror_abort
,
1214 .pause
= mirror_pause
,
1215 .complete
= mirror_complete
,
1216 .cancel
= mirror_cancel
,
1218 .drained_poll
= mirror_drained_poll
,
1221 static const BlockJobDriver commit_active_job_driver
= {
1223 .instance_size
= sizeof(MirrorBlockJob
),
1224 .job_type
= JOB_TYPE_COMMIT
,
1225 .free
= block_job_free
,
1226 .user_resume
= block_job_user_resume
,
1228 .prepare
= mirror_prepare
,
1229 .abort
= mirror_abort
,
1230 .pause
= mirror_pause
,
1231 .complete
= mirror_complete
,
1232 .cancel
= commit_active_cancel
,
1234 .drained_poll
= mirror_drained_poll
,
1237 static void coroutine_fn
1238 do_sync_target_write(MirrorBlockJob
*job
, MirrorMethod method
,
1239 uint64_t offset
, uint64_t bytes
,
1240 QEMUIOVector
*qiov
, int flags
)
1243 size_t qiov_offset
= 0;
1244 int64_t bitmap_offset
, bitmap_end
;
1246 if (!QEMU_IS_ALIGNED(offset
, job
->granularity
) &&
1247 bdrv_dirty_bitmap_get(job
->dirty_bitmap
, offset
))
1250 * Dirty unaligned padding: ignore it.
1253 * 1. If we copy it, we can't reset corresponding bit in
1254 * dirty_bitmap as there may be some "dirty" bytes still not
1256 * 2. It's already dirty, so skipping it we don't diverge mirror
1259 * Note, that because of this, guest write may have no contribution
1260 * into mirror converge, but that's not bad, as we have background
1261 * process of mirroring. If under some bad circumstances (high guest
1262 * IO load) background process starve, we will not converge anyway,
1263 * even if each write will contribute, as guest is not guaranteed to
1264 * rewrite the whole disk.
1266 qiov_offset
= QEMU_ALIGN_UP(offset
, job
->granularity
) - offset
;
1267 if (bytes
<= qiov_offset
) {
1268 /* nothing to do after shrink */
1271 offset
+= qiov_offset
;
1272 bytes
-= qiov_offset
;
1275 if (!QEMU_IS_ALIGNED(offset
+ bytes
, job
->granularity
) &&
1276 bdrv_dirty_bitmap_get(job
->dirty_bitmap
, offset
+ bytes
- 1))
1278 uint64_t tail
= (offset
+ bytes
) % job
->granularity
;
1280 if (bytes
<= tail
) {
1281 /* nothing to do after shrink */
1288 * Tails are either clean or shrunk, so for bitmap resetting
1289 * we safely align the range down.
1291 bitmap_offset
= QEMU_ALIGN_UP(offset
, job
->granularity
);
1292 bitmap_end
= QEMU_ALIGN_DOWN(offset
+ bytes
, job
->granularity
);
1293 if (bitmap_offset
< bitmap_end
) {
1294 bdrv_reset_dirty_bitmap(job
->dirty_bitmap
, bitmap_offset
,
1295 bitmap_end
- bitmap_offset
);
1298 job_progress_increase_remaining(&job
->common
.job
, bytes
);
1301 case MIRROR_METHOD_COPY
:
1302 ret
= blk_co_pwritev_part(job
->target
, offset
, bytes
,
1303 qiov
, qiov_offset
, flags
);
1306 case MIRROR_METHOD_ZERO
:
1308 ret
= blk_co_pwrite_zeroes(job
->target
, offset
, bytes
, flags
);
1311 case MIRROR_METHOD_DISCARD
:
1313 ret
= blk_co_pdiscard(job
->target
, offset
, bytes
);
1321 job_progress_update(&job
->common
.job
, bytes
);
1323 BlockErrorAction action
;
1326 * We failed, so we should mark dirty the whole area, aligned up.
1327 * Note that we don't care about shrunk tails if any: they were dirty
1328 * at function start, and they must be still dirty, as we've locked
1329 * the region for in-flight op.
1331 bitmap_offset
= QEMU_ALIGN_DOWN(offset
, job
->granularity
);
1332 bitmap_end
= QEMU_ALIGN_UP(offset
+ bytes
, job
->granularity
);
1333 bdrv_set_dirty_bitmap(job
->dirty_bitmap
, bitmap_offset
,
1334 bitmap_end
- bitmap_offset
);
1335 job
->actively_synced
= false;
1337 action
= mirror_error_action(job
, false, -ret
);
1338 if (action
== BLOCK_ERROR_ACTION_REPORT
) {
1346 static MirrorOp
*coroutine_fn
active_write_prepare(MirrorBlockJob
*s
,
1351 uint64_t start_chunk
= offset
/ s
->granularity
;
1352 uint64_t end_chunk
= DIV_ROUND_UP(offset
+ bytes
, s
->granularity
);
1354 op
= g_new(MirrorOp
, 1);
1359 .is_active_write
= true,
1360 .is_in_flight
= true,
1361 .co
= qemu_coroutine_self(),
1363 qemu_co_queue_init(&op
->waiting_requests
);
1364 QTAILQ_INSERT_TAIL(&s
->ops_in_flight
, op
, next
);
1366 s
->in_active_write_counter
++;
1368 mirror_wait_on_conflicts(op
, s
, offset
, bytes
);
1370 bitmap_set(s
->in_flight_bitmap
, start_chunk
, end_chunk
- start_chunk
);
1375 static void coroutine_fn
active_write_settle(MirrorOp
*op
)
1377 uint64_t start_chunk
= op
->offset
/ op
->s
->granularity
;
1378 uint64_t end_chunk
= DIV_ROUND_UP(op
->offset
+ op
->bytes
,
1379 op
->s
->granularity
);
1381 if (!--op
->s
->in_active_write_counter
&& op
->s
->actively_synced
) {
1382 BdrvChild
*source
= op
->s
->mirror_top_bs
->backing
;
1384 if (QLIST_FIRST(&source
->bs
->parents
) == source
&&
1385 QLIST_NEXT(source
, next_parent
) == NULL
)
1387 /* Assert that we are back in sync once all active write
1388 * operations are settled.
1389 * Note that we can only assert this if the mirror node
1390 * is the source node's only parent. */
1391 assert(!bdrv_get_dirty_count(op
->s
->dirty_bitmap
));
1394 bitmap_clear(op
->s
->in_flight_bitmap
, start_chunk
, end_chunk
- start_chunk
);
1395 QTAILQ_REMOVE(&op
->s
->ops_in_flight
, op
, next
);
1396 qemu_co_queue_restart_all(&op
->waiting_requests
);
1400 static int coroutine_fn
bdrv_mirror_top_preadv(BlockDriverState
*bs
,
1401 int64_t offset
, int64_t bytes
, QEMUIOVector
*qiov
, BdrvRequestFlags flags
)
1403 return bdrv_co_preadv(bs
->backing
, offset
, bytes
, qiov
, flags
);
1406 static int coroutine_fn
bdrv_mirror_top_do_write(BlockDriverState
*bs
,
1407 MirrorMethod method
, uint64_t offset
, uint64_t bytes
, QEMUIOVector
*qiov
,
1410 MirrorOp
*op
= NULL
;
1411 MirrorBDSOpaque
*s
= bs
->opaque
;
1413 bool copy_to_target
;
1415 copy_to_target
= s
->job
->ret
>= 0 &&
1416 !job_is_cancelled(&s
->job
->common
.job
) &&
1417 s
->job
->copy_mode
== MIRROR_COPY_MODE_WRITE_BLOCKING
;
1419 if (copy_to_target
) {
1420 op
= active_write_prepare(s
->job
, offset
, bytes
);
1424 case MIRROR_METHOD_COPY
:
1425 ret
= bdrv_co_pwritev(bs
->backing
, offset
, bytes
, qiov
, flags
);
1428 case MIRROR_METHOD_ZERO
:
1429 ret
= bdrv_co_pwrite_zeroes(bs
->backing
, offset
, bytes
, flags
);
1432 case MIRROR_METHOD_DISCARD
:
1433 ret
= bdrv_co_pdiscard(bs
->backing
, offset
, bytes
);
1444 if (copy_to_target
) {
1445 do_sync_target_write(s
->job
, method
, offset
, bytes
, qiov
, flags
);
1449 if (copy_to_target
) {
1450 active_write_settle(op
);
1455 static int coroutine_fn
bdrv_mirror_top_pwritev(BlockDriverState
*bs
,
1456 int64_t offset
, int64_t bytes
, QEMUIOVector
*qiov
, BdrvRequestFlags flags
)
1458 MirrorBDSOpaque
*s
= bs
->opaque
;
1459 QEMUIOVector bounce_qiov
;
1462 bool copy_to_target
;
1464 copy_to_target
= s
->job
->ret
>= 0 &&
1465 !job_is_cancelled(&s
->job
->common
.job
) &&
1466 s
->job
->copy_mode
== MIRROR_COPY_MODE_WRITE_BLOCKING
;
1468 if (copy_to_target
) {
1469 /* The guest might concurrently modify the data to write; but
1470 * the data on source and destination must match, so we have
1471 * to use a bounce buffer if we are going to write to the
1473 bounce_buf
= qemu_blockalign(bs
, bytes
);
1474 iov_to_buf_full(qiov
->iov
, qiov
->niov
, 0, bounce_buf
, bytes
);
1476 qemu_iovec_init(&bounce_qiov
, 1);
1477 qemu_iovec_add(&bounce_qiov
, bounce_buf
, bytes
);
1478 qiov
= &bounce_qiov
;
1481 ret
= bdrv_mirror_top_do_write(bs
, MIRROR_METHOD_COPY
, offset
, bytes
, qiov
,
1484 if (copy_to_target
) {
1485 qemu_iovec_destroy(&bounce_qiov
);
1486 qemu_vfree(bounce_buf
);
1492 static int coroutine_fn
bdrv_mirror_top_flush(BlockDriverState
*bs
)
1494 if (bs
->backing
== NULL
) {
1495 /* we can be here after failed bdrv_append in mirror_start_job */
1498 return bdrv_co_flush(bs
->backing
->bs
);
1501 static int coroutine_fn
bdrv_mirror_top_pwrite_zeroes(BlockDriverState
*bs
,
1502 int64_t offset
, int64_t bytes
, BdrvRequestFlags flags
)
1504 return bdrv_mirror_top_do_write(bs
, MIRROR_METHOD_ZERO
, offset
, bytes
, NULL
,
1508 static int coroutine_fn
bdrv_mirror_top_pdiscard(BlockDriverState
*bs
,
1509 int64_t offset
, int64_t bytes
)
1511 return bdrv_mirror_top_do_write(bs
, MIRROR_METHOD_DISCARD
, offset
, bytes
,
1515 static void bdrv_mirror_top_refresh_filename(BlockDriverState
*bs
)
1517 if (bs
->backing
== NULL
) {
1518 /* we can be here after failed bdrv_attach_child in
1519 * bdrv_set_backing_hd */
1522 pstrcpy(bs
->exact_filename
, sizeof(bs
->exact_filename
),
1523 bs
->backing
->bs
->filename
);
1526 static void bdrv_mirror_top_child_perm(BlockDriverState
*bs
, BdrvChild
*c
,
1528 BlockReopenQueue
*reopen_queue
,
1529 uint64_t perm
, uint64_t shared
,
1530 uint64_t *nperm
, uint64_t *nshared
)
1532 MirrorBDSOpaque
*s
= bs
->opaque
;
1536 * If the job is to be stopped, we do not need to forward
1537 * anything to the real image.
1540 *nshared
= BLK_PERM_ALL
;
1544 bdrv_default_perms(bs
, c
, role
, reopen_queue
,
1545 perm
, shared
, nperm
, nshared
);
1549 * For commit jobs, we cannot take CONSISTENT_READ, because
1550 * that permission is unshared for everything above the base
1551 * node (except for filters on the base node).
1552 * We also have to force-share the WRITE permission, or
1553 * otherwise we would block ourselves at the base node (if
1554 * writes are blocked for a node, they are also blocked for
1555 * its backing file).
1556 * (We could also share RESIZE, because it may be needed for
1557 * the target if its size is less than the top node's; but
1558 * bdrv_default_perms_for_cow() automatically shares RESIZE
1559 * for backing nodes if WRITE is shared, so there is no need
1562 *nperm
&= ~BLK_PERM_CONSISTENT_READ
;
1563 *nshared
|= BLK_PERM_WRITE
;
1567 /* Dummy node that provides consistent read to its users without requiring it
1568 * from its backing file and that allows writes on the backing file chain. */
1569 static BlockDriver bdrv_mirror_top
= {
1570 .format_name
= "mirror_top",
1571 .bdrv_co_preadv
= bdrv_mirror_top_preadv
,
1572 .bdrv_co_pwritev
= bdrv_mirror_top_pwritev
,
1573 .bdrv_co_pwrite_zeroes
= bdrv_mirror_top_pwrite_zeroes
,
1574 .bdrv_co_pdiscard
= bdrv_mirror_top_pdiscard
,
1575 .bdrv_co_flush
= bdrv_mirror_top_flush
,
1576 .bdrv_refresh_filename
= bdrv_mirror_top_refresh_filename
,
1577 .bdrv_child_perm
= bdrv_mirror_top_child_perm
,
1582 static BlockJob
*mirror_start_job(
1583 const char *job_id
, BlockDriverState
*bs
,
1584 int creation_flags
, BlockDriverState
*target
,
1585 const char *replaces
, int64_t speed
,
1586 uint32_t granularity
, int64_t buf_size
,
1587 BlockMirrorBackingMode backing_mode
,
1589 BlockdevOnError on_source_error
,
1590 BlockdevOnError on_target_error
,
1592 BlockCompletionFunc
*cb
,
1594 const BlockJobDriver
*driver
,
1595 bool is_none_mode
, BlockDriverState
*base
,
1596 bool auto_complete
, const char *filter_node_name
,
1597 bool is_mirror
, MirrorCopyMode copy_mode
,
1601 MirrorBDSOpaque
*bs_opaque
;
1602 BlockDriverState
*mirror_top_bs
;
1603 bool target_is_backing
;
1604 uint64_t target_perms
, target_shared_perms
;
1607 if (granularity
== 0) {
1608 granularity
= bdrv_get_default_bitmap_granularity(target
);
1611 assert(is_power_of_2(granularity
));
1614 error_setg(errp
, "Invalid parameter 'buf-size'");
1618 if (buf_size
== 0) {
1619 buf_size
= DEFAULT_MIRROR_BUF_SIZE
;
1622 if (bdrv_skip_filters(bs
) == bdrv_skip_filters(target
)) {
1623 error_setg(errp
, "Can't mirror node into itself");
1627 target_is_backing
= bdrv_chain_contains(bs
, target
);
1629 /* In the case of active commit, add dummy driver to provide consistent
1630 * reads on the top, while disabling it in the intermediate nodes, and make
1631 * the backing chain writable. */
1632 mirror_top_bs
= bdrv_new_open_driver(&bdrv_mirror_top
, filter_node_name
,
1634 if (mirror_top_bs
== NULL
) {
1637 if (!filter_node_name
) {
1638 mirror_top_bs
->implicit
= true;
1641 /* So that we can always drop this node */
1642 mirror_top_bs
->never_freeze
= true;
1644 mirror_top_bs
->total_sectors
= bs
->total_sectors
;
1645 mirror_top_bs
->supported_write_flags
= BDRV_REQ_WRITE_UNCHANGED
;
1646 mirror_top_bs
->supported_zero_flags
= BDRV_REQ_WRITE_UNCHANGED
|
1647 BDRV_REQ_NO_FALLBACK
;
1648 bs_opaque
= g_new0(MirrorBDSOpaque
, 1);
1649 mirror_top_bs
->opaque
= bs_opaque
;
1651 bs_opaque
->is_commit
= target_is_backing
;
1653 bdrv_drained_begin(bs
);
1654 ret
= bdrv_append(mirror_top_bs
, bs
, errp
);
1655 bdrv_drained_end(bs
);
1658 bdrv_unref(mirror_top_bs
);
1662 /* Make sure that the source is not resized while the job is running */
1663 s
= block_job_create(job_id
, driver
, NULL
, mirror_top_bs
,
1664 BLK_PERM_CONSISTENT_READ
,
1665 BLK_PERM_CONSISTENT_READ
| BLK_PERM_WRITE_UNCHANGED
|
1666 BLK_PERM_WRITE
, speed
,
1667 creation_flags
, cb
, opaque
, errp
);
1673 /* The block job now has a reference to this node */
1674 bdrv_unref(mirror_top_bs
);
1676 s
->mirror_top_bs
= mirror_top_bs
;
1678 /* No resize for the target either; while the mirror is still running, a
1679 * consistent read isn't necessarily possible. We could possibly allow
1680 * writes and graph modifications, though it would likely defeat the
1681 * purpose of a mirror, so leave them blocked for now.
1683 * In the case of active commit, things look a bit different, though,
1684 * because the target is an already populated backing file in active use.
1685 * We can allow anything except resize there.*/
1687 target_perms
= BLK_PERM_WRITE
;
1688 target_shared_perms
= BLK_PERM_WRITE_UNCHANGED
;
1690 if (target_is_backing
) {
1691 int64_t bs_size
, target_size
;
1692 bs_size
= bdrv_getlength(bs
);
1694 error_setg_errno(errp
, -bs_size
,
1695 "Could not inquire top image size");
1699 target_size
= bdrv_getlength(target
);
1700 if (target_size
< 0) {
1701 error_setg_errno(errp
, -target_size
,
1702 "Could not inquire base image size");
1706 if (target_size
< bs_size
) {
1707 target_perms
|= BLK_PERM_RESIZE
;
1710 target_shared_perms
|= BLK_PERM_CONSISTENT_READ
| BLK_PERM_WRITE
;
1711 } else if (bdrv_chain_contains(bs
, bdrv_skip_filters(target
))) {
1713 * We may want to allow this in the future, but it would
1714 * require taking some extra care.
1716 error_setg(errp
, "Cannot mirror to a filter on top of a node in the "
1717 "source's backing chain");
1721 s
->target
= blk_new(s
->common
.job
.aio_context
,
1722 target_perms
, target_shared_perms
);
1723 ret
= blk_insert_bs(s
->target
, target
, errp
);
1728 /* XXX: Mirror target could be a NBD server of target QEMU in the case
1729 * of non-shared block migration. To allow migration completion, we
1730 * have to allow "inactivate" of the target BB. When that happens, we
1731 * know the job is drained, and the vcpus are stopped, so no write
1732 * operation will be performed. Block layer already has assertions to
1734 blk_set_force_allow_inactivate(s
->target
);
1736 blk_set_allow_aio_context_change(s
->target
, true);
1737 blk_set_disable_request_queuing(s
->target
, true);
1739 s
->replaces
= g_strdup(replaces
);
1740 s
->on_source_error
= on_source_error
;
1741 s
->on_target_error
= on_target_error
;
1742 s
->is_none_mode
= is_none_mode
;
1743 s
->backing_mode
= backing_mode
;
1744 s
->zero_target
= zero_target
;
1745 s
->copy_mode
= copy_mode
;
1747 s
->base_overlay
= bdrv_find_overlay(bs
, base
);
1748 s
->granularity
= granularity
;
1749 s
->buf_size
= ROUND_UP(buf_size
, granularity
);
1751 if (auto_complete
) {
1752 s
->should_complete
= true;
1755 s
->dirty_bitmap
= bdrv_create_dirty_bitmap(bs
, granularity
, NULL
, errp
);
1756 if (!s
->dirty_bitmap
) {
1759 if (s
->copy_mode
== MIRROR_COPY_MODE_WRITE_BLOCKING
) {
1760 bdrv_disable_dirty_bitmap(s
->dirty_bitmap
);
1763 ret
= block_job_add_bdrv(&s
->common
, "source", bs
, 0,
1764 BLK_PERM_WRITE_UNCHANGED
| BLK_PERM_WRITE
|
1765 BLK_PERM_CONSISTENT_READ
,
1771 /* Required permissions are already taken with blk_new() */
1772 block_job_add_bdrv(&s
->common
, "target", target
, 0, BLK_PERM_ALL
,
1775 /* In commit_active_start() all intermediate nodes disappear, so
1776 * any jobs in them must be blocked */
1777 if (target_is_backing
) {
1778 BlockDriverState
*iter
, *filtered_target
;
1779 uint64_t iter_shared_perms
;
1782 * The topmost node with
1783 * bdrv_skip_filters(filtered_target) == bdrv_skip_filters(target)
1785 filtered_target
= bdrv_cow_bs(bdrv_find_overlay(bs
, target
));
1787 assert(bdrv_skip_filters(filtered_target
) ==
1788 bdrv_skip_filters(target
));
1791 * XXX BLK_PERM_WRITE needs to be allowed so we don't block
1792 * ourselves at s->base (if writes are blocked for a node, they are
1793 * also blocked for its backing file). The other options would be a
1794 * second filter driver above s->base (== target).
1796 iter_shared_perms
= BLK_PERM_WRITE_UNCHANGED
| BLK_PERM_WRITE
;
1798 for (iter
= bdrv_filter_or_cow_bs(bs
); iter
!= target
;
1799 iter
= bdrv_filter_or_cow_bs(iter
))
1801 if (iter
== filtered_target
) {
1803 * From here on, all nodes are filters on the base.
1804 * This allows us to share BLK_PERM_CONSISTENT_READ.
1806 iter_shared_perms
|= BLK_PERM_CONSISTENT_READ
;
1809 ret
= block_job_add_bdrv(&s
->common
, "intermediate node", iter
, 0,
1810 iter_shared_perms
, errp
);
1816 if (bdrv_freeze_backing_chain(mirror_top_bs
, target
, errp
) < 0) {
1821 QTAILQ_INIT(&s
->ops_in_flight
);
1823 trace_mirror_start(bs
, s
, opaque
);
1824 job_start(&s
->common
.job
);
1830 /* Make sure this BDS does not go away until we have completed the graph
1832 bdrv_ref(mirror_top_bs
);
1834 g_free(s
->replaces
);
1835 blk_unref(s
->target
);
1836 bs_opaque
->job
= NULL
;
1837 if (s
->dirty_bitmap
) {
1838 bdrv_release_dirty_bitmap(s
->dirty_bitmap
);
1840 job_early_fail(&s
->common
.job
);
1843 bs_opaque
->stop
= true;
1844 bdrv_child_refresh_perms(mirror_top_bs
, mirror_top_bs
->backing
,
1846 bdrv_replace_node(mirror_top_bs
, mirror_top_bs
->backing
->bs
, &error_abort
);
1848 bdrv_unref(mirror_top_bs
);
1853 void mirror_start(const char *job_id
, BlockDriverState
*bs
,
1854 BlockDriverState
*target
, const char *replaces
,
1855 int creation_flags
, int64_t speed
,
1856 uint32_t granularity
, int64_t buf_size
,
1857 MirrorSyncMode mode
, BlockMirrorBackingMode backing_mode
,
1859 BlockdevOnError on_source_error
,
1860 BlockdevOnError on_target_error
,
1861 bool unmap
, const char *filter_node_name
,
1862 MirrorCopyMode copy_mode
, Error
**errp
)
1865 BlockDriverState
*base
;
1867 if ((mode
== MIRROR_SYNC_MODE_INCREMENTAL
) ||
1868 (mode
== MIRROR_SYNC_MODE_BITMAP
)) {
1869 error_setg(errp
, "Sync mode '%s' not supported",
1870 MirrorSyncMode_str(mode
));
1873 is_none_mode
= mode
== MIRROR_SYNC_MODE_NONE
;
1874 base
= mode
== MIRROR_SYNC_MODE_TOP
? bdrv_backing_chain_next(bs
) : NULL
;
1875 mirror_start_job(job_id
, bs
, creation_flags
, target
, replaces
,
1876 speed
, granularity
, buf_size
, backing_mode
, zero_target
,
1877 on_source_error
, on_target_error
, unmap
, NULL
, NULL
,
1878 &mirror_job_driver
, is_none_mode
, base
, false,
1879 filter_node_name
, true, copy_mode
, errp
);
1882 BlockJob
*commit_active_start(const char *job_id
, BlockDriverState
*bs
,
1883 BlockDriverState
*base
, int creation_flags
,
1884 int64_t speed
, BlockdevOnError on_error
,
1885 const char *filter_node_name
,
1886 BlockCompletionFunc
*cb
, void *opaque
,
1887 bool auto_complete
, Error
**errp
)
1889 bool base_read_only
;
1892 base_read_only
= bdrv_is_read_only(base
);
1894 if (base_read_only
) {
1895 if (bdrv_reopen_set_read_only(base
, false, errp
) < 0) {
1900 job
= mirror_start_job(
1901 job_id
, bs
, creation_flags
, base
, NULL
, speed
, 0, 0,
1902 MIRROR_LEAVE_BACKING_CHAIN
, false,
1903 on_error
, on_error
, true, cb
, opaque
,
1904 &commit_active_job_driver
, false, base
, auto_complete
,
1905 filter_node_name
, false, MIRROR_COPY_MODE_BACKGROUND
,
1908 goto error_restore_flags
;
1913 error_restore_flags
:
1914 /* ignore error and errp for bdrv_reopen, because we want to propagate
1915 * the original error */
1916 if (base_read_only
) {
1917 bdrv_reopen_set_read_only(base
, true, NULL
);